Apparatus for irradiation of laser cavity

ABSTRACT

A system for the irradiation of a target with electromagnetic energies covering the region between approximately the infra-Xray and the trans-infrared portions of the spectrum comprises: light associated with a shock wave front aligned to strike a tape valve comprising a movable tape, impervious to said shock wave, having a mirror-like surface and also at least one aperture in spaced relation to said surface and means for moving said tape at a speed such that said light strikes the mirror-like surface and said shock wave front passes through said aperture; a shock sensitive irradiable target optically coupled to said mirror-like surface and said movable member, whereby to provide via said movable member a light-coupling between said target and light source.

[111 3,821,660 June 28, 1974 APPARATUS FOR IRRADIATION OF LASER CAVITY[75 Inventors: Jer-Yu Shang, Wilmington, Del.;

William B. Hansel, Media, Pa.

[73] Assignee: Sun Research and Development Co.,

Philadelphia, Pa.

22 Filed: June 12, 1972 21 Appl. No.: 261,764

Related US. Application Data [63] Continuation-impart of Ser. No. 3,964,Jan. 19

1970, abandoned.

OTHER PUBLICATIONS Stokes et al., Tech. Report Announced in US. Govt.

Res. & Devel. Reports, 69, (5), March 10, 1969, p. 156.

Primary Examiner-David Schonberg Assistant ExaminerR. J. WebsterAttorney, Agent, or Firm-George L. Church, Esq.; J. Edward Hess, Esq.;Barry A. Bisson, Esq.

[ 5 7] ABSTRACT A system for the irradiation of a target withelectromagnetic energies covering the region between approximately theinfra-X-ray and the trans-infrared portions of the spectrum comprises:light associated with a shock wave front aligned to strike a tape valvecomprising a movable tape, impervious to said shock wave, having amirror-like surface and also at least one aperture in spaced relation tosaid surface and means for moving said tape at a speed such that saidlight strikes the mirror-like surface and said shock wave front passesthrough said aperture; a shock sensitive irradiable target opticallycoupled to said mirrorlike surface and said movable member, whereby toprovide via said movable member a light-coupling between said target andlight source.

8 Claims, 6 Drawing Figures LASER FROM INTERNAL COMBUSTlON ENGINEFUEL-AIR MIXTURE PISTON SPARK PLUG ENGINE HEAD LIGHT WAVE DIAGRAM FIGUREI SIIEEI 1W3 LASER FROM INTERNAL COMBUSTION ENGINE SPARK PLUG hr ENGINEHEAD LIGHT FUEL-AIR MIXTURE FIGURE 2 WAVE DIAGRAM IOO /o REFLECTIVE C IINVENTORS i JER-YU SHANG GD CD I BY WILLIAM BLHANSEL PARTIALTRANSMISSION PATENTEMwzs m4 SHHT 2 (IF 3 SPARK PLUG FEGURE 3 [5 I4 v //1COAXIAL L s i 1. 7\ G? |8 2O LASER I I9 CAVITY ryl TRANSVERSE M Q I TAPEVALVE FIGURE 4 /TAPE VALVE MIRRORED TAPE VALVE INVENTORS JER-YU SHANG BYWILLIAM B. HANSEL ATTORNY PKTIDJUNZB B74 SHEET 3 OF 3 FIGURE 5 SECTION"A-A" FIGURE 6 ENTOR INV JER-YU SHANG WILLIAM B. HANSEL ATTORNEYAPPARATUS FOR IRRADIATION OF LASER CAVITY CROSS REFERENCE TO RELATEDAPPLICATIONS This application is a continuation-in-part of ourapplication Ser. No. 3,964 filed Jan. 19, I970, abandoned and is alsorelated to Ser. No. 3,966 of Jer-Yu Shang, filed Jan. 19, 1970, now US.Pat. No. 3,719,454 issued Mar. 6, 1973. The disclosure of both of theseapplications is hereby incorporated herein.

BACKGROUND OF THE INVENTION The maser or the laser can be used to causethe ejection of energy from an excited molecule. The frequencies from amaser or laser radiation can be electronically tuned to a finite rangeto excite certain portions of a given molecule and cause localexcitation in a very short time interval. Then the excitation(vibrational and electronical) is transferred to another part of themolecule. This is known as relaxation phenomenon. Energy can beextracted from a reaction system by emitting the characteristicradiation from the final products in the form of laser or maser action.This has been demonstrated, for example, by Dr. Irwin Wieder in Phys.Letters 13, 759 (1967) (see also Chem. Eng. July 31, I967 pp. 48, orChem. Eng. News June 26, I967). The Wieder device is operated by atechnique called chemi-optical resonant pumping, whereby radiation frommolecules newly formed in flames is absorbed by identical moleculesphysically separated from the combustion or reacting apparatus.

The Wieder device uses a tube of carbon dioxide gas in a laser cavityand radiation from a carbon monoxide flame. Continuous output power of lmilliwatt of infrared energy is reported. The carbon dioxide iscontained at 0.3 to 13 torr in a quartz tube 4 meters long. Mirrors ateach end of the tube have a 99.5 percent reflectivity for light at 10.6microns, the wave length of a carbon dioxide laser beam. On two sides ofthe tube, and extending the full length of it, is a series of burnersfed with carbon monoxide.

When the carbon monoxide burns, carbon dioxide in a highly excitedenergy state results. Some of this en-' ergy radiates through the wallsof the quartz tube to raise the entrapped carbon dioxide from the groundenergy level to an excited state. Lasing results when photons areemitted from the excited carbon dioxide as it drops to a lower energystate. Another means of irradiation of a laser cavity is disclosed byDeMent in US. Pat. No. 3,414,838 and involves irradiation of a target(e.g., a laser cavity) with electromagnetic energy (e.g., light) bymeans of a combination of a shock producing light source aligned tostrike a breakable reflective optic upon activation of the light source,wherein the breakable reflective optic is optically coupled to the lightsource and the irradiable target is optically coupled to the breakableoptic, whereby to provide via the breakable optic a light-couplingbetween the target and the light source.

BRIEF DESCRIPTION OF THE INVENTION The invention involves means forirradiation of a laser cavity and includes processes and apparatus. Oneembodiment is an apparatus comprising an irradiable target and means forthe irradiation of said target with electromagnetic energies coveringthe region between approximately the infra-X-ray and the trans-infraredportions of the spectrum, said menas comprising: means for generatinglight and an associated shock wave front and a gas flow passage which isaligned so that said light and said shock wave front can strike saidtape valve, said tape valve comprising a movable member having amirror-like surface and also an aperture in spaced relation to saidsurface and means for moving said member at a speed such that said lightstrikes the mirror-like surface and said movable member to provide viasaid movable member a light-coupling between said target and lightsource, and wherein saidtape valve comprises a tape impervious to saidshock wave and at least one aperture in said tape and means for drivingsaid tape at a high velocity between two aligned portions of saidpassage and for moving said tape transversely with respect to the lengthof said passage, said aperture which when moved into' registry with saidtwo aligned portions comprises the opening of said valve permittingcommunication between said aligned passage portions, and means formaintaining said tape centered in the gap between said aligned portions,as the tape moves, said means providing application of oppositelydirected gas flows to the respective opposite faces of the tape.

In one preferred embodiment the apparatus includes critical floworifices and means wherein said oppositely directed gas flows areproduced within said critical flow orifices, thereby permittingequilization of the pressure on each side of said movable member andpreventing contact of said movable member with said aligned portions.

In the present invention, energy at a given frequency is extracted fromthe luminosity associated with a shock front, (which can involve achemical reaction such as combustion) by means of a laser cavitycontaining a material (solid, liquid or gas) which can be excited by theenergy and caused to limit laser light (or quantized energy). The lasercavity can be incorporated in the interior portion of a wave reactor orwithin the combustion chamber of an internal combustion engine. Thelaser cavity can also be external to the combustion chamber. Thus, thelaser cavity can be of the resonance or the pump types; however, theinvention is usually of greater utility with a laser resonant cavity.The interior surface of the wave reactor or internal combustion engineshould be highly reflective, such as a mirrored surface and can includemeans (e.g., wipers, brushes, gas jets, etc.) for maintaining part orall of said surface in a clean reflective condition.

The resulting laser light can be used for many applications, such ascommunication, machinery, weapons (see for example US. Pat. No.3,414,838 for a listing of such applications).

A laser cavity enclosed within a wave engine (or wave reactor) can beused to produce a rapidly pulsed laser beam by converting the luminosityassociated with a shock wave front into laser light. An especiallyuseful source of such mechanical energy for powering a wave engine ishigh pressure natural gas. In the wave engine mechanical energy (e.g.,gas pressure) is transformed into light and heat energy. The wave engineis a wave reactor when this light and/or heat energy is used to triggera desired chemical reaction.

The light associated with the combustion of fuel (including theluminosity associated with the shock front produced by the combustion)in an internal combustion engine can also be caused to produce laserlight by incorporation of a laser cavity within the combustion chamberof the engine. More preferably, the laser cavity is external to thecombustion chamber and the luminosity or light associated with the shockwave front is separated from the shock wave by means of a mirroredtape-valve and the so separated light is caused to irradiate the lasercavity (e.g., see FIG. 4). The shock wave can also be kept separate fromthe laser cavity by providing the wall of the combustion chamber with alight transmitting shock barrier (e.g., a quartz. window); however, sucha window suffers from the disadvantage that it can become fouled byimpurities or additives in the feed (e.g., lead oxides) or by carbonproduced by incomplete combustion of a hydrocarbon fuel.

When the shock wave generated in a continuous shock wave reactor ispassed through a gas (e. g., argon, carbon dioxide, light hydrocarbon),the extreme compression of the gas in the shock front rapidly heats andexcites (sometimes causing decomposition of the gas). This, in turn,causes intense light emission. This light (just as light from a flame orexplosion) can be used to pump various lasers (with appropriateprecautions so that the shock wave from the explosion does not shatterthe laser itself).

There are a number of ways of arranging lasers inside a continuous shockwave reactor (or an internal combustion engine) such as forming a ringof lasers, imbedding a ring of lasers in the wall of the shock wavereactor or engine, etc. One arrangement is the concentric coaxialmonolaser illustrated in FIG. 5 of the drawmgs.

Cynogen, CN, burning in oxygen generates an extremely energetic flamewhich can be used to pump ruby rods for brief periods (see C. S. Stokesand L. A. Streng investigation of Several High Temperature Reactionslnvolving Cyanogen and Like Compounds as High Brightness ChemicalPyrotechnic Sources," USGRDR. Mar. 10, 1969, Vol. 69, No. 5, p. 156,which was received by the US. Patent Office on June 6, I969). Weakcontinuous wave (or CW) laser action on the 10.6 wave length CO lasertransition can also be excited by pumping the CO gas with a surroundingflame from gas jets supplied with CO and 0 If mixtures of cynogen/oxygen(CN/O carbon monoxide/oxygen (CO/O and light hydrocarbon vapors aresubjected to shock wave compression in a continuous shock wave reactor,such as that as shown in FIG. 5, coherent laser radiation will result.

The present invention, in a preferred embodiment, utilizes a continuousshock wave generator, which is actuated by a fast opening-closing valve,such as the tape valve of W. B. Hansels U.S. Pat. No. 3,500,862, issuedMar. 17, 1970 (the disclosure of which is incorporated herein byreference).

The Hansel tape valve is an impervious tape which is driven at a highvelocity between two aligned portions of a gas flow passage, the tapemoving transversely with respect to the length of the passage. The tapehas an aperture therein which comes into registry with the two passageportions to permit communication therebetween for opening of the valve.The tape is maintained centered in a small gap between the juxtaposedpassage portions, as the tape moves, by the application of(oppositely-acting) gas pressures to the respective opposite faces ofthe tape.

The basic principle of the tape valve involves the use of a number ofcritical flow orifices behind the tape, opposite to the high pressureside of the tape valve. These critical orifices generate sufficient backpressure to counterbalance the pressure from the high pressure side. Thetape valve must have a self-acting servomechanism to keep the tape fromcoming unduly close to the sides, at the two sides of the tape. Amechanical valve mechanism syncronized with the tape can permit thereacted gases to escape and be collected as final products.

There are many natural gas wells in the western part of Texas. Thesewells generate high pressure gases which can be used as a mechanicalenergy source in the continuous shock wave reactor.

Be feeding oxygen into the wave reactor, the natural gas can beconverted to useful products (such as ethene or propylene).Alternatively, fluorine gas can be fed into the wave reactor and caused(by the shock excitation) to react with the natural gas to producefluorinated hydrocarbons and HF.

DESCRIPTION OF THE DRAWINGS A laser is a device that converts differentforms of energy into a concentrated beam of coherent electromagneticradiation. When a system is in thermal equilibrium, most of the atomsoccupy the lowest possible energy levels, i.e., they are in the groundstate. Atoms in the ground state can be excited to higher energy levelsby pumping, i.e., by causing them to absorb energy from some externalsource. An atom in such an excited state may then relax to a lowerenergy state, known as the metastable state, by releasing some of theabsorbed energy. A second energy release, wherein the material goes fromthe metastable state to the ground state is the energy which can betransformed to a laser beam. For such an energy transfer to result in alaser beam, it is necessary to have an active laser material, anoptically resonant cavity, and means whereby external energy can excitethe laser material. When sufficient energy is absorbed by the material,its energy characteristics change and it becomes an emitter of coherentelectromagnetic radiation. For example, in a gas laser the output can becontinuous and the discharge is made directly in the laser material.

Stimulated emission is the process which occurs when the light emittedfrom one atom interacts with another atom that is still in the excitedstate.

In the accompanying drawings FIG. 1 illustrates a combination of a laserwith an internal combustion engme.

In FIG. 1 the engine has an intake valve 1, an exhaust valve 2 and acombustion chamber 3 where fuel-air mixture is ignited (as by a sparkplug or by compression). Hydrocarbons (e.g., natural gas, gasoline ordiesel fuel) are the usual fuels although other combustibles can be used(such as nitromethane, ethers, alcohols, ammonia, etc). In thisembodiment it is preferred that the laser be placed in the region behindthe reflected shock wave. Thisregion (designated by a circled 5 in FIG.2) can be determined by a plot of time (t) v. distance (x) asillustrated in drawing A of FIG. 2. FIG. 2 also, in the lower drawing C,illustrates the three major areas encountered in a shock tube or wavereactor.

In A and C of FIG. 2, the circled l is the region in front of the shockfront;

circled 2 signifies the region behind the shock front and before theinterface;

circled 3 is the region behind the interface and the reflected expansionwave;

circled 4 signifies the region behind the expansion wave; and

circled 5 is the region behind the reflected shock wave.

In the sole invention of Jer-Yu Shang (which is claimed in hisco-pending application Ser. No. 3,966 filed of even date with our parentapplication Ser. No. 3,964) which combines a shock tube and a laser, thearea of the shock tube behind the reflected shock wave is converted intoa laser cavity. This is accomplished by mirroring two opposite sides ofthe interior of the shock tube in the area behind the reflected shockwave. One

front-coated mirror is made partially transmitting for the desired wavelength of laser light (e. g., 99.5 percent reflection); thus causinglasing of the excited gases in the region labeled with the circled 5producing. laser light which leaves the shock tube through the partiallytransmitting mirror. Also shown in FIG. 2 at sketch B on the far rightis a plot of time (t) v. pressure (P) encountered in a wave reactor.This plot illustrates the appreciable and abrupt change in the pressuregradient which, along with supersonic flow phenomena, is characteristicof the shock process. The Shang combination can convert both collisionenergy and light into laser energy.

The mathematical relationships illustrated in FIG. 2 are discussed indetail in the following prior art publications:

SHOCK TUBES, J. K. Wright, Pages 29-31 (1961), Wiley & Sons Inc.

SHOCK WAVES IN CHEMISTRY AND PHYSICS, John N. Bradley, Pages 52-55 and189-9, Wiley & Sons, N.Y.

CHEMICAL REACTIONS IN SHOCK WAVES, Edward F. Greene, and J. PeterToennies, Pages 125-7 (I964), Academic Press Inc.

FUNDAMENTALS'OF GAS DYNAMICS, Jerzy A. Owczarek, Pages 390-5 (1964),International Text Book Co., Scranton, Pa.

FIG. 3 illustrates two possible configurations of a laser which isexterior to the internal combustion engine, and which is excited bymoving a tape valve such that light from the interior of the internalcombustion engine passes through the orifice of the tape valve andirradiates the laser. Instead of a tape valve, the opening in the enginehead can be sealed with a lighttransmitting window (e.g., quartz). FIG.3 illustrates two positions, relative to the light producing shocksource (the internal combustion engine) in which the laser can beplaced. In the upper configuration, the

laser cavity is coaxial to the light-producing shock source (alsoillustrated is a replaceable protective nose cone 16). In the lowerarrangement the laser cavity (21) is transverse to the light-producingshock source. In either arrangement it is preferred that the interior ofthe shock tube (13 and I8) and the interior of the combustion chamber 8of the internal combustion engine be highly reflective (e.g.,mirror-like). In FIG. 3 the shock tube containing the laser is providedwith an intake valve (14 and I9) and an exhause valve (15 and Thesevalves allow chemical reactants, or excitable gases such as xenon orneon, to enter the shock tube, and be withdrawn, thus chemical productscan be obtained or an expensive transfer agent (e.g., xenon) can berecovered and recycled. The internal combustion engine can be otherwiseused in a conventional manner (e.g., the piston 9, via rod 10 cantransmit power to a crank-shaft 11), to power a vehicle or drill, togenerate electrical power, etc.

FIG. 4 illustrates a preferred embodiment of the present inventioninvolving irradiation of an irradiable target (e.g., a laser cavity)with electromagnetic energies covering the region between approximatelythe infra- X-ray and the trans-infrared portions of the spectrum bymeans of the system which comprises: light associated with a shock wavefront (e.g., producedwithin 22 an internal combustion engine) aligned tostrike a movable member having a mirror-like surface and also anaperture (or orifice) in spaced relation to said surface (e.g., amirrored tape valve) and means for moving said member at a speed suchthat said light strikes the mirror-like surface and said shock wavefront passes through said aperture; an irradiable target (e.g., a laser)optically coupled to said mirror-like surface and said movable member,whereby to provide via said movable member a light-coupling between saidtarget and light source. FIG. 4 also includes a second tape valvesimilar to that in FIG. 3, which can be used to regulate the passage ofshock and light into the hollow conduit 30.

In FIGS. 5 and 6 there is illustrated a combination of a laser cavityand a wave reactor and/or wave engine. This invention can be used toproduce a rapidly pulsed laser. That is, it can convert the mechanicalenergy of a shock wave into a laser light in a quasi continuous fashion.In FIG. 5, a shock tube 60 encloses a laser cavity 62 which contains alaserable material which can be a solid (e.g., ruby), liquid or gas(e.g., CO In the wave engine a pressure differential exists on oppositesides of a metal tape 66. To the left of the tape is a source of higherpressure gases than on the right of the tape. Tape 66 moves at highspeed (as by oscillation-- but preferably is a continuous band, like aband-saw blade), such that the orifice AA (shown in the section view ofFIG. 6) alternately allows the high pressure gas on the left to enterthe shock wave tube. For further description of the wave engine or wavereactor see US. Pat. No. 3,300,283 of Lauer et al., issued Jan. 24,1967; US. Pat. No. 3,307,917 of Hansel et al., issued Mar. 7, 1967; US.Pat. No. 3,357,797 of Hansel, issued Dec. 12, I967; US. Pat. No.3,500,862 issued Mar. 17, I970 of Hansel; US. Pat. No. 3,307,918 ofBodmer et al., issued Mar. 7, 1967; US. Pat. No. 3,355,256 of Hansel,issued Nov. 28, 1967; and US. Pat. No. 3,384,117 of Hansel, issued May21, 1968.

Critical flow orifices 68 and 69 allow equilization of the pressure tothe left such that gases emerging through ports 71 and 73 prevent themetal tape 66 from rubbing against the shock tube. The gases producingthe shock wave, can be vented from the shock tube by a mechanicallyoperated valve, such as the beveled gear system, 85 and 84, whichactivates a stop-cock type valve arrangement for venting of the drivengas. Similarly, the driven gas is vented through the stopcockarrangement 74 and 75 which is activated by the beveled gear arrangement78 and 79.

,When the high pressure gas enters through the orifice AA into theright-hand side of the chamber (the shock tube), an expansion wave meetsa shock wave in the region between the ports 74 and 80. The regionbehind the reflected shock wave contains highly excited gases. Theseexcited gases pass from the excited state to a metastable state and, inpassing from the metastable state to ground state, produce radiationwhich causes lasing of the laserable material in the laser cavity 62resulting in the production of a laser beam 63. Preferably the lasercavity (if the coaxial position illustrated in the drawing) is protectedby a replaceable nose cone 64 or by arrangements described by Ladermanet 211., Applied Optics, Vol. 8, No. 8, 1743- (1969).

The size of the engine required to produce a desired amount of laserpower can be determined as follows:

a, calculate needed photon pumping flux,, b. calculate size andtemperature of shock front having luminosity needed to provide pumpingflux, c. calculate shock front parameters to give needed luminosity, d.calculate engine size to give the needed shock system. Such calculationis applicable to both the internal combustion engine and to pressuredgas sources as me-v chanical drivers for a wave reactor (or engine).

Where it is desired that a given chemical product be recovered from thewave reactor, such a product can be removed by means of the stop-cocktype valve arrangement and vents 80, 81 or 74, 75. The combination of alaser cavity with a wave reactor can be used to produce laser radiationand desired chemical products (e.g., methane and nitrogen can beconverted to hydrogen cyanide and acetylene by causing the reactants tobe rapidly heated, by the shock source, to a temperature of 3500F, orgreater, followed almost immediately by cooling to l600F. or less, thecooling rate being in the same order of magnitude as the heating rate).The combination can be used as a source of heat energy and laser energyand can involve combustion of a hydrocarbon (e.g., gasoline plus oxygen)or any carbonaceous material, even carbon powder suspended in air.

The combination of an internal combustion engine or a wave engine and alaser cavity is particularly useful as a portable source of laser light,as for guidance in drilling wells or tunnels.

An additional and important utility which can be obtained by combining alaser cavity and a wave engine or wave reactor of the type illustratedin FIGS. 5 and 6, is in thefield of long-range communication. That is,the rate of movement of the tape and the size and spacing of theopenings in the tape can be utilized to control the amount and timing ofthe pulses of the laser energy emitted and, if this energy is directedat a suitable receptor (or reflector that is directed at a receptor) theamplitude, quantity and patterning of the pulses of laser energy can betranslated by the receiver into a message.

In general, a preferred class of lasable materials comprises compoundsof the following elements: Ag, Al, B, Ba, Be, C, Ca, Cd, Cr, Fe, Ge, Hg,Li, Mg, Mn, Na, Pb, Ru, Si, Sr, Ta. Ti, U, V, W, Zn and Zr. The devicein U.S. Pat. No. 3,434,072 of M. Birnbaum, issued Mar. 18, 1969, can beutilized with these and additional elements as the laser portion of theclaimed combination and others disclosed herein.

The invention claimed is:

1. An apparatus comprising an irradiable target and means for theirradiation of said target with electromagnetic energies covering theregion between approximately the infra-X-ray and the trans-infraredportions of the spectrum, said means comprising: means for generatinglight and an associated shock wave front and a gas flow passage which isaligned so that said light and a shock wave front can strike said tapevalve, said tape valve comprising a movable tape member having amirror-like surface and also at least one aperture in said tape andmeans for moving said member at a speed such that said light strikes themirror-like surface and said shock wave front passes through saidaperture; and wherein said irradiable target is optically coupled tosaid mirror-like surface and said movable member to provide via saidmovable member a light-coupling between said target and light source,and wherein said movable member is impervious to said shock wave andwherein said moving means comprises means for driving said tape at ahigh velocity between two aligned portions of said passage and formoving said tape transversely with respect to the length of saidpassage, said aperture which when moved into registry with said twoaligned portions comprises the opening of said valve permittingcommunication between said aligned passage portions, and means formaintaining said tape centered in the gap between said aligned portions,as the tape moves, said means providing application of oppositelydirected gas flows to the respective opposite faces of the tape.

2. The combination of claim 1 wherein said system includes critical floworifices and wherein said oppositely directed gas flows are producedwithin said critical flow orifices thereby permitting equilization ofthe pressure on each side of said movable member and preventing contactof said movable member with said aligned portions.

3. The combination of claim 1 wherein said light and said shock wavefront are produced within an internal combustion engine.

4. The combination of claim 1 wherein means are included for introducingxenon into the region behind the reflected shock wave.

S. The combination of claim 1 wherein means are included for maintainingcarbon dioxide in the laser cavity.

6. The combination of claim I wherein said light and shock wave frontare produced within a wave reactor.

least one additional reagent.

1. An apparatus comprising an irradiable target and means for theirradiation of said target with electromagnetic energies covering theregion between approximately the infra-X-ray and the trans-infraredportions of the spectrum, said means comprising: means for generatinglight and an associated shock wave front and a gas flow passage which isaligned so that said light and a shock wave front can strike said tapevalve, said tape valve comprising a movable tape member having amirror-like surface and also at least one aperture in said tape andmeans for moving said member at a speed such that said light strikes themirror-like surface and said shock wave front passes through saidaperture; and wherein said irradiable target is optically coupled tosaid mirror-like surface and said movable member to provide via saidmovable member a light-coupling between said target and light source,and wherein said movable member is impervious to said shock wave andwherein said moving means comprises means for driving said tape at ahigh velocity between two aligned portions of said passage and formoving said tape transversely with respect to the length of saidpassage, said aperture which when moved into registry with said twoaligned portions comprises the opening of said valve permittingcommunication between said aligned passage portions, and means formaintaining said tape centered in the gap between said aligned portions,as the tape moves, said means providing application of oppositelydirected gas flows to the respective opposite faces of the tape.
 2. Thecombination of claim 1 wherein said system includes critical floworifices and wherein said oppositely directed gas flows are producedwithin said critical flow orifices thereby permitting equilization ofthe pressure on each side of said movable member and preventing contactof said movable member with said aligned portions.
 3. The combination ofclaim 1 wherein said light and said shock wave front are produced withinan internal combustion engine.
 4. The combination of claim 1 whereinmeans are included for introducing xenon into the region behind thereflected shock wave.
 5. The combination of claim 1 wherein means areincluded for maintaining carbon dioxide in the laser cavity.
 6. Thecombination of claim 1 wherein said light and shock wave front areproduced within a wave rEactor.
 7. The combination of claim 6 whereinmeans are included for producing said shock wave front utilizing agaseous hydrocarbon under high pressure.
 8. The combination of claim 7wherein means are included for causing said shock wave front to initiatea chemical reaction involving said hydrocarbon and at least oneadditional reagent.